The present invention relates to a solar module, and in particular to a photovoltaic device using an amorphous semiconductor, that is, an amorphous solar module. More particularly, it relates to a solar module for outdoor use having improved passivation.
In contrast to crystalline solar cells, solar cells made from amorphous semiconductors, such as amorphous silicon, are characterized as being easily fabricated on various kinds of substrates, such as glass, metal, resin, and so forth, at relatively low temperatures. Accordingly, fairly small-scale solar modules, where a solar module is defined as, for example, a structure having a passivating layer over connected solar cells, are typically fabricated by forming a solar cell element comprising layers of conductive metal oxide, amorphous semiconductor, and metal electrode on a glass substrate, and then passivating the structure by vacuum lamination of a resin sheet having an undercoated adhesive layer. Since a robust structure is required for practical use, it is necessary to strengthen this type of solar module, and as a result, larger-sized modules have usually been made by constructing an array of solar submodules on tempered or laminated glass, where each submodule comprises a conductive metal oxide layer, an amorphous semiconductor layer and a metal electrode layer fabricated on a glass substrate. After making the electrical contacts, the module is passivated by vacuum lamination of a resin sheet which is undercoated with an adhesive layer.
A major problem in fabricating this type of large-scale solar module is that, as described above, the manufacturing process is complex, consisting of several steps, such as arranging the solar submodules on the tempered glass, making the electrical connections, vacuum laminating and so forth, in addition to the submodule fabrication steps. Further, because expensive vacuum equipment is required, there are other problems of increased manufacturing cost and reduced reliability.
The present invention has been realized in consideration of these kinds of problems inherent in the previous technology, and accordingly, the object of this invention is to provide a solar module which can be effectively passivated by using simple steps and convenient techniques.